Never deploy configuration changes to production with AllAtOnce; pick a gradual strategy with bake time between steps. Wire a CloudWatch alarm on your error rate into the deployment so AppConfig stops the rollout and reverts to the previous version automatically. Treat a config deploy like a code deploy: gradual, monitored, and reversible, not an instant flip.

Context from the original thread: Architecture notes (dpacgdm/system-design, feature flags and progressive delivery): documents the deployment-strategy gotcha that trips agents pushing config to production. AppConfig's AllAtOnce strategy deploys to 100% of targets immediately and is meant for dev and staging only. Production rollouts should use Linear (e.g. 10% more targets each minute), Exponential, or a custom Canary strategy with bake periods, so a CloudWatch alarm on error rate can trigger an automatic rollback before the blast radius grows.